1. Field of the Invention
A system whereby a wheeled truck can be selectively placed into a superposed position upon a hydraulically-actuated lifting table assembly. When in position the lift table assembly mates to the truck, prior to lifting it to any desired vertical elevation. The present invention relates generally to a very efficient material handling system, and particularly a cooperation between a wheeled truck and a vertically extendable lift table assembly.
Lift tables per se are known in the prior art, and, of course, wheeled push-type trucks are also per se well known in the prior art. The present invention involves a synergistic cooperation between a modified form of wheeled truck, and a modified lifting table assembly, allowing increased efficiency in material handling, in environments such as supermarkets wherein small pallets must often times be lifted and moved at various locations.
2. Description of the Prior Art
Numerous devices are known in the prior art for allowing a table to be lifted to a vertical height. Applicant has conducted a search, and is aware of the following prior patents:
______________________________________ Great Britain 619,431 Great Britain 1,337,853 Germany 468,832 King Re. 27,914 Sexton 1,813,429 Ross 2,402,579 Stewart 2,489,056 Saunders 2,833,587 ______________________________________
In summary, these noted patents illustrate various forms of elevating truck-like devices, though in each case the approach has been to incorporate an elevating mechanism upon a wheeled sub-carriage. In contrast, the present invention employs a single lifting table sub-carriage assembly, of essentially conventional construction, with the ability to cooperate with the underside of numerous wheeled truck assemblies. With this system a number of modified trucks can be selectively placed upon the lifting table, and the lifting table can be selectively moved to various positions, for example, to load various pallets at shelves in a supermarket environment.
The 1949 Great Britain Pat. No. 619,431 illustrates an elevated truck which is typical of systems wherein a single rolling mechanism is employed, for both lifting and movement of a truck. In contrast, the present concept devolves to mating a modified platform truck with an otherwise stationary lifting mechanism, for selective lifting of the truck.
Great Britain Pat. No. 1,337,853 shown another form of lifting truck, together with an hydrualic power cylinder, for lifting the carriage off the ground. This patent shows a specific improvement through a post, which allows pivoting of the truck, when in the raised position.
The German patent illustrates a prior art jack-like device, using a scissor mechanism to engage a separable platform-like member, for certain particular raising jobs. However, there is no suggestion of a system wherein wheel trucks are selectively mated to a lifting table, as taught herein.
The King patent shows yet another portable lifting table, with a particular form of linkage which reduces initial raising forces. Here again, the King patent illustrates the prior art approach of using a superposed linking mechanism upon a rolling sub-frame, in complete distinction to the present system wherein a lift table is located below, and in mating relationship to a wheeled platform-truck.
The additionally noted references are supplied simply to further illustrate well-known forms of scissor mechanisms, and particularly scissor mechanisms for performing a jacking function, for lifting loads. In applicant's opinion, the prior art does not suggest combining a mating platform truck above a lifting table device, for a most economical and efficient raising of the truck to a desired elevation. These patents represent the prior art presently known to applicant, and collectively illustrate that the present invention involves a departure from prior thinking. This departure amounts to a savings, since only one lifting platform need be supplied, with perhaps, several mating wheeled truck assemblies.